I want to do a large glue-up collage on a building with composite-siding (cinder block underneath).

If I use wheat paste for my adhesive, can it be power-washed off successfully after 2-3 months without destroying the siding? If something only needed to stay up for 1-4 weeks, what adhesive would you go with?

It’s not a permanent installation unfortunately, so I have to troubleshoot removal…

So, I live in Berlin and of course I have never ever sprayed on a spot where that wasn't perfectly legal or put up stickers or anything...
Now, I have things I'd like to do in a couple of spots where there is a lot of activity and I'm have no idea about any of the rules.
Quite beautiful narrow passage, not strictly puiblic, but as the passage leads to a cinema, a small museum and two bars, it gets traffic.
Only spaces not covered in a ever changing pattern of Graffiti, Stickers, YarnBombing and even sculptures, is the ground. (I'll grab you guys some pics next time I'm there)
I have no idea what the rules there are. Taggers keep away from it. Which is grand for the aesthetic, but severely limits my contacts and eh... any ideas how to figure out the do's and don'ts?

Yes, I'm very aware how country-bumpkin this sounds, but I have been a country bumpkin growing up and I'm now more at an age were people buy houses, or kids, have dogs with their spouses... that kind of thing... instead of discovering their interest in streetart...